Mill with auxilarry spindle

Thanks again.
I modified the hal file in line with the post i mentioned earlier and Linuxcnc now opens. With the settings i had for position control i get the error, " joint 3 following error. I've played around with the max velocity and acceleration as well as ferror and min ferror without success. I've tried using m3s1000 to no avail.
I've also tried changing Axis 3 in the ini file that suggested in the above post again without success. The change was to delete the Axis 3 element and replace it with:-
[AXIS_3]
STEPGEN_MAXACCEL = 1125.0
SCALE = 100
I've reduced these two parameters; no joy.
I'm sailing round in a sea of uncertainty and perhaps the problem still lies in the hal file!

To combine both position mode (for A Axis use) and velocity mode (for spindle use)
is fairly complicated. I think it can be done with one stepgen in velocity mode
but requires a PID component and a bunch of signal re-routing depending on mode
plus dealing with the following error issue.

With software stepping, I suspect the simplest way would be to
have two stepgens (adding one to your existing configuration) ,
one setup in normal position mode for the A axis and one setup in velocity
mode for spindle use.

Then whatever signal you use for changing modes routes either the A axis
step/dir pins or the spindle step/dir pins to the physical parallel port pins
using either a mux_generic or a couple of lut5 components in hal to select which
stepgens step/dir pins get routed to the hal parallel port pins that drive the A axis/spindle.

If you dont need A axis gcode at all but just a variable speed, its much simpler .
You would just delete all the A Axis setup in your ini file and connections in you hal
file and just set the spindle velocity in the gcode.

PCW wrote: To combine both position mode (for A Axis use) and velocity mode (for spindle use)
is fairly complicated. I think it can be done with one stepgen in velocity mode
but requires a PID component and a bunch of signal re-routing depending on mode.

Here is a picture:

wiki.linuxcnc.org/cgi-bin/wiki.pl?SpindleOrient

Note that is showing the config for a VFD, but the principle is very similar for a velocity-mode stepgen.